1. Field of the Invention
The present invention relates to a recording apparatus and a method for controlling the recording apparatus.
2. Description of the Related Art
In recent years, in devices that operate on supplied power, there has been strong requirement that power consumption should be reduced to decrease running cost and prevent environmental destruction.
For example, to reduce power consumption, various devices are provided with a power source control unit that includes an automatic power-off function to turn off power supply when a preset time elapses. This is intended to cut down on wasteful power consumption at night when the devices and appliances are less frequently used.
Multifunction printers (hereafter referred to as MFP) equipped with functions in addition to printing, such as a copy function and a fax function are now starting to positively comply with various energy conservation standards.
However, in order to realize high-speed operation in response to the expanding functions in most advanced printers (e.g., MFPs), the internal clock has been made faster and electric power consumption is increasing.
Many inkjet recording apparatuses are provided with a power saving mode in which if, for example, a non-operating state or a non-use state continues for a given length of time, only certain functions are allowed to operate and other functions are deactivated. Since the power saving mode is intended to reduce power consumption, it is generally configured to stop the main power supply and the main clock.
As for another configuration of power saving mode, Japanese Patent Laid-Open No. 2000-347762 discusses a power saving mode in which specific peripheral circuits operate at a lower clock frequency than in a normal operation. Japanese Patent Laid-Open No. 2003-110762 discusses a still another configuration of power saving mode in which when the power-off state of external devices connected to the recording apparatus is detected and a stand-alone function is not being executed, the normal power mode is switched to a power saving mode. Japanese Patent Laid-Open No. 2006-31537 discusses a still further configuration of power saving mode, which includes a normal power consumption mode and two power saving modes, and in which a decision is made in advance which power saving mode should be set before the normal power consumption mode is switched over to a power saving mode.
Memory devices having a card slot into which a memory card is inserted is in wide spread public use in recent years. However, in memory devices including a slot for mounting a storage function such as a memory card, there is a problem that when the recording apparatus is connected to a higher-level device (host PC), it may be impossible to switch to a power saving mode. The reason for that is that there are some operating systems (OS) in certain host PCs, which frequently issue a command to inquire about presence or absence of a memory card. Also, there are some applications which issue a command to inquire about the capacity of the card. Furthermore, in some cases, the printer driver resident in the host PC periodically makes inquiries about the status of the printer.
In response to each inquiry, it is necessary for the recording apparatus side to access the memory card, acquire necessary information, and send information to the host PC. To access the memory card, it may be required that the CPU is in a normal operation. Therefore, even after the recording apparatus has entered a power saving mode, if such an inquiry arrives, it may be necessary to immediately shift from the power saving mode to the normal power mode to respond to the inquiry. As a result of repeatedly making such transitions, power consumption increases or the life of electronic parts is shortened contrary to the saving efforts. Therefore, a transition to a power saving mode may not take place if the recording apparatus is connected to the host PC.
In Japanese Patent Laid-Open No. 2000-347762, clocks are continually supplied to specific peripheral circuits at all times. According to this configuration, even when the operation stops for a predetermined length of time, the clock cannot be stopped, and more reduction of power consumption cannot be realized. Furthermore, in Japanese Patent Laid-Open No. 2003-110762, unless the power supply to the external devices connected to the main body is turned off, the transition to a power saving mode cannot be effected.
Therefore, for example, when the printer is connected to the PC and power is supplied to the PC, the printer may not shift to the power saving mode. In the configuration shown in Japanese Patent Laid-Open No. 2006-31537, in order to shift from one power saving mode to another power saving mode, it is necessary to return once to the normal power consumption mode, which increases waste of electric power. Moreover, since it is required to decide beforehand the power saving mode that is to be entered, control of the device becomes more complex.